- August 16, 2010 at 8:42 pm
The concept behind the Sentinel lymph node biopsy is this: they inject radioactive tracer in the center of where your mole was removed. That tracer follows the natural lymph drainage paths to the first lymph node. This is the Sentinel Node. (Sometime, there is more than one sentinel node). When you start cutting out large chunks of skin, you may change the drainage paths. So if you do the Sentinel Lymph node biopsy AFTER the wide excision, the drainage path may not be the same path as before the wide excision. Since you want to test the sentinel lymph node to see if any melanoma is there, you don't want to have any change in the drainage paths. That basically means a sentinel node biopsy done after the wide excision may be useless. No one can guarantee that the same sentinel node would be taken.
So, I suggest you call the dermatologist again and ask why he hasn't scheduled you for a SNB. The general cutoff for having a SNB is 1.00mm. You are well beyond that. Yes, you don't have to have one. Yes, it is mostly done as a diagnostic tool. If you have melanoma in the lymph node, they typically remove all those nodes and possibly offer you treatment or clinical trial or observation. If you don't have the SNB, you would want to be monitored very closely.
Please continue to research and talk to your dermatologist about the sentinel node biopsy. It's possible they didn't schedule it because of insurance…. but they should give you all the costs and pros and cons and let you decide.